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1.
Ecotoxicol Environ Saf ; 186: 109743, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31593827

RESUMO

Nanoparticles (NPs) production is increasing worldwide. These products are likely to end up in aquatic environments. However, few studies evaluated the chronic toxicity of iron-based NPs (Fe-NPs) to cladocerans and their potential ecotoxicological hazards. In this study we aimed to investigate the effects of iron oxide nanoparticles (Fe3O4-NPs) to Ceriodaphnia silvestrii Daday, 1902, assessing acute (48 h) and chronic toxicity (up to 14 d). Besides traditional endpoints (immobility and lethality), we also evaluated physiological responses (respiration rates) in a 48 h-exposure. No immobility was observed (EC50 > 100 mg L-1) after 48 h, whereas respiration rates at the highest concentration were 400% of that in control, indicating that this endpoint was more sensitive during acute toxicity. In chronic assays, Fe3O4-NPs affected body length (8.24% growth inhibition in 7 d-exposure) and number of eggs (7-d IC10: 3.53, IC20: 6.69 mg Fe L-1) and neonates (7-d IC10: 1.25, IC20: 3.75 mg Fe L-1). Based on species sensitivity distribution (SSD), C. silvestrii was a sensitive organism, suggesting Fe-NPs as a possible threat for this species. Our results also indicate that the NPs caused a physical barrier, impairing food absorption, since we observed NPs agglomerations into cladocerans' gut. We demonstrate that Fe3O4-NPs affects C. silvestrii metabolism and reproduction and our results support the use of sublethal endpoints to assess environmental safety. The release of these NPs into freshwater environments should be carefully evaluated, since disturbances on cladoceran population dynamics could cause strong impacts on the entire food web structure and ultimately on ecosystem functioning.


Assuntos
Cladóceros/efeitos dos fármacos , Nanopartículas de Magnetita/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Cladóceros/fisiologia , Ecossistema , Reprodução/efeitos dos fármacos , Testes de Toxicidade
2.
Sci Total Environ ; 697: 134107, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31476512

RESUMO

We evaluated the ability of diffusive gradients in thin films (DGT) to assess the effects of water hardness and dissolved organic carbon (DOC consisting of humic acids) on Cu and Zn toxicity (i.e., 48 h LC50s) to Ceriodaphnia dubia. When DOC was high, Cu concentrations measured by DGT (DGT Cu) were significantly lower than Cu concentrations in water (dissolved Cu), and DGT LC50s were significantly lower than LC50s based on dissolved concentrations. When DOC was low, differences between dissolved Cu and DGT Cu were small, as were differences between dissolved LC50s and DGT LC50s. Differences between DGT and dissolved measurements of Zn were small compared with the differences observed for Cu, and DGT Zn LC50s were relatively similar to dissolved Zn LC50s. Humic acids formed strong organic-Cu complexes that were both inaccessible for biological uptake and excluded by DGT, which selected for free or weakly bound Cu. In contrast, Zn did not form strong complexes with DOC that greatly affected either toxicity or the measurement of Zn by DGT. The effects of hardness on DGT measurements of Cu and Zn were smaller and more complex than the effects of DOC. Large, statistically significant differences between DGT measurements of Cu in low and high DOC water accurately reflected the strong effects of DOC on Cu toxicity. However, the effects of DOC were inconsistent for Zn, and DGT provided less information about the toxic fraction of this metal.


Assuntos
Cladóceros/fisiologia , Metais/toxicidade , Poluentes Químicos da Água/toxicidade , Água/química , Animais , Metais/química , Testes de Toxicidade , Poluentes Químicos da Água/química
3.
Artigo em Inglês | MEDLINE | ID: mdl-31390928

RESUMO

Cladocerans are constantly exposed to humic substances in nature, yet the effects of these substances on their survival and reproduction are not well known. Here, the effects of humic substances (20 and 40 mg L-1) (HS) on the life history variables of three common cladocerans, Ceriodaphnia dubia, Moina macrocopa, and Daphnia pulex were evaluated. The results showed that the effect of humic substances on the tested cladocerans is species-specific, affecting either survival, reproduction or both. For M. macrocopa, exposed to HS at a concentration of 40 mg L-1, the average lifespan and the life expectancy at birth were significantly reduced as compared to controls, but for C. dubia and D. pulex these parameters were increased. Gross reproductive rate was unaffected by the HS level for both D. pulex and M. macrocopa, but it was significantly higher for C. dubia. When compared to the corresponding controls, for HS-exposed cladocerans, the rate of population increase was significantly reduced in case of D. pulex while it was stimulated for both C. dubia and M. macrocopa. It appears that humic substances had a slightly stronger influence on survivorship than on reproduction of the tested cladocerans.


Assuntos
Cladóceros/efeitos dos fármacos , Substâncias Húmicas/efeitos adversos , Reprodução/efeitos dos fármacos , Animais , Cladóceros/fisiologia , Daphnia/efeitos dos fármacos , Demografia , Feminino , Substâncias Húmicas/análise , Masculino , Especificidade da Espécie
4.
Sci Total Environ ; 696: 133909, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31454606

RESUMO

Cyanobacteria blooms are increasing globally, with further increases predicted in association with climate change. Recently, some cyanobacteria species have been identified as a source of estrogenic effects in aquatic animals. To explore possible estrogenic effects of Microcystis aeruginosa (an often-dominant cyanobacteria species) on zooplankton, we examined effects of cyanobacteria exudates (MaE, 2 × 104 and 4 × 105 cells/ml) on reproduction in Daphnia magna. We analyzed physiological, biochemical and molecular characteristics of exposed Daphnia via both chronic and acute exposures. MaE at both low and high cell density enhanced egg number (15.4% and 23.3%, respectively) and reproduction (37.7% and 52.4%, respectively) in D. magna similar to 10 µg/L estradiol exposure. In addition, both MaE of low and high cell densities increased population growth rate (15.8% and 19.6%, respectively) and reproductive potential (60% and 83%, respectively) of D. magna. These exudates promoted D. magna reproduction by stimulating 17ß-hydroxysteroid-dehydrogenase (17ß-HSD) activity and production of ecdysone and juvenile hormone, and by enhancing vitellogenin biosynthesis via up-regulating expression of Vtg1 and Vtg2. However, increased expression (6.6 times higher than controls) of a detoxification gene (CYP360A8) indicated that MaE might also induce toxicity in D. magna. Reproductive interference of zooplankton by blooming cyanobacteria might negatively affect foodwebs because MaE-induced zooplankton population increase would enhance grazing and reduce abundance of edible algae, thereby adding to the list of known disruptive properties of cyanobacterial blooms.


Assuntos
Cladóceros/fisiologia , Cianobactérias/crescimento & desenvolvimento , Congêneres do Estradiol , Eutrofização , Animais , Cianobactérias/metabolismo , Daphnia , Estradiol , Estrogênios , Microcystis , Reprodução , Poluentes Químicos da Água/toxicidade , Zooplâncton
5.
Sci Total Environ ; 686: 246-253, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31181512

RESUMO

Nanoparticles (NPs) often serve as carriers of background toxins and enhance their toxicity on aquatic organisms such as Ceriodaphnia dubia (C. dubia). However, foods, especially algae, are also present in natural water and impacts this type of toxicity. This study investigated the effect of algae on the combined toxicity of nano-TiO2 and lead (Pb). A mixture of yeast-trout chow-cereal leaves (YTC) was also used as another model food. Results indicated that, both algae and YTC significantly reduce the combined toxicity of nano-TiO2 and Pb. Further investigation indicated that the ingestion of algae had minimal impacts on Pb uptake by, Pb depuration from, and Pb distribution within the C. dubia. Therefore, the toxicity reduction from algae ingestion should come from mechanisms other than the change in Pb mass and speciation in C. dubia, which will need future investigation. Nevertheless, the effect of food on the mitigation of combined toxicity of NPs and heavy metals must be considered when assessing the toxicity of nanoparticles in the natural environment because food always exists in natural waterbodies where aquatic organisms grow.


Assuntos
Clorófitas/fisiologia , Cladóceros/fisiologia , Chumbo/toxicidade , Titânio/toxicidade , Animais , Nanopartículas/toxicidade , Testes de Toxicidade , Poluentes Químicos da Água/toxicidade
6.
PLoS One ; 14(3): e0214013, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30901351

RESUMO

Filter feeding zooplankton are a crucial component of limnic food webs. Copepods and cladocerans are important prey organisms for first-level predators like the common and abundant larvae of phantom midges (Chaoborus sp.). The latter possess a complex catching basket built of head appendages specialized to capture small crustaceans. The predator-prey-relationship of Chaoborus (Diptera, Nematocera) and Daphnia (Crustacea, Cladocera) has been studied in particular detail owing to the daphniids' ability to react upon the threat of predation with inducible defenses. Daphnia pulex expresses so-called 'neckteeth' in the presence of Chaoborus larvae that are discussed as a defensive trait that interferes with the larval head appendages and their effectiveness has been shown in several studies. Nonetheless, mode of function of these neckteeth is not understood and the hypothesis that they interfere with the predator's head appendages still has to be confirmed. To clarify the role of neckteeth in Daphnia, an understanding of the Chaoborus capture apparatus is essential. Here, we present a detailed three-dimensional analysis of Chaoborus obscuripes' larval head morphology as well as a kinematic analysis of the attack motion, which revealed an impressive strike velocity (14 ms to prey contact). The movement of the larvae's head appendages is reconstructed in the three-dimensional space using a combination of high-speed videography, micro-computed tomography and computer animation. Furthermore, we provide predation trial data to distinguish between pre- and post-attack defensive effects in D. pulex. Our findings suggest a combination of pre- and post-attack defenses with an average effectiveness of 50% each. With this study, we quantitatively describe prey capture kinematics of C. obscuripes and take a further step to reveal the neckteeth' mode of function in D. pulex.


Assuntos
Cladóceros/fisiologia , Copépodes/fisiologia , Dípteros/fisiologia , Larva/fisiologia , Comportamento Predatório/fisiologia , Animais , Cadeia Alimentar , Cabeça/fisiologia
7.
Environ Toxicol Pharmacol ; 68: 4-12, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30849701

RESUMO

In the field of nanoecotoxicology, very few reports have focused on biochemical changes in non-target organisms after nanoexposure. A less explored aquatic non-target crustacean, Moina macrocopa, was used in the present study to analyze toxicity effects of gold nanoparticles (AuNPs), an emerging nanomaterial. AuNPs was fabricated using tannic acid and were 29 ± 2 nm in size. The 48 h LC50 value of AuNPs was 14 ± 0.14 mg/L against M. macrocopa. The sub-lethal exposure of M. macrocopa juveniles to AuNPs (1.47 and 2.95 mg/L) decreased the activities of acetyl cholinesterase and digestive enzymes (trypsin and amylase). A concentration dependant increase in the activities of antioxidant enzymes such as catalase, superoxide dismutase and glutathione S-transferase suggested the generation of oxidative stress in M. macrocopa after AuNPs exposure. Changes in enzyme activity can be utilized as biomarker(s) for early detection of nanoparticle contamination in aquatic habitat. AuNPs accumulation in gut of M. macrocopa increased the metal bio burden (11 mg/L) and exhibited inhibitory action on digestive enzymes. Complete depuration of AuNPs was not observed after transferring nano-exposed M. macrocopa to normal medium without AuNPs. AuNPs tended to adhere on external body parts such as setae, carapace of M. macrocopa which interfered with swimming activity and also changed the behavioral pattern. AuNPs underwent agglomeration in the medium used for maintenance of M. macrocopa. As nanomaterials are emerging pollutants in aquatic systems, the present work highlights the hazardous effect of AuNPs and development of enzymatic biomarkers to curtail it at community level.


Assuntos
Cladóceros/efeitos dos fármacos , Ouro/toxicidade , Nanopartículas Metálicas/toxicidade , Poluentes Químicos da Água/toxicidade , Acetilcolinesterase/metabolismo , Amilases/metabolismo , Animais , Comportamento Animal/efeitos dos fármacos , Catalase/metabolismo , Cladóceros/fisiologia , Glutationa Transferase/metabolismo , Frequência Cardíaca/efeitos dos fármacos , Dose Letal Mediana , Superóxido Dismutase/metabolismo , Testes de Toxicidade/métodos , Tripsina/metabolismo
8.
Environ Sci Pollut Res Int ; 26(11): 10916-10925, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30783928

RESUMO

Daphniopsis tibetana Sars lives in elevation, usually with strong solar UV radiation. We speculate that UV may have an effect on the ecology and evolutionary biology of this species. However, the regulatory effect and mechanism of UV on D. tibetana have not been studied previously. Here, our results showed that UVB could act as a positive factor in the relative body lengths, reproductive parameters, and population growth parameters of D. tibetana when UVB radiation is 20-170 mJ cm-2, compared with the control group. Strikingly, these parameters were highest at 120 mJ cm-2. To explore the mechanism underlying the UVB irradiation effects, we conducted a transcriptome analysis using the Trinity platform. The results indicated that differentially regulated genes were mostly enriched in lipid transport and lipid localization by Gene Ontology (GO) enrichment analysis of 146 differentially expressed genes (83 upregulated and 63 downregulated). This is the first study of UVB radiation of D. tibetana to reveal genes that may have crucial roles in survival, growth, and reproduction and could be candidates for future functional studies. Additionally, the study could supply a substantial resource for investigating and elucidating lipids that could play important roles in a physiological context.


Assuntos
Cladóceros/efeitos da radiação , Monitoramento Ambiental/métodos , Raios Ultravioleta , Animais , China , Cladóceros/genética , Cladóceros/crescimento & desenvolvimento , Cladóceros/fisiologia , Relação Dose-Resposta à Radiação , Expressão Gênica/efeitos da radiação , Perfilação da Expressão Gênica , Lagos/química , Modelos Teóricos , Dinâmica Populacional , Reprodução/efeitos da radiação , Salinidade , Análise de Sobrevida
9.
Environ Toxicol Chem ; 38(3): 511-523, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30776146

RESUMO

We compared 2 statistical hypothesis-test approaches (no-observed-effect concentration [NOEC] and test of significant toxicity [TST]) to determine the influence of laboratory test performance on the false-positive error rate using the US Environmental Protection Agency's Ceriodaphnia dubia reproduction whole-effluent toxicity (WET) test endpoint. Simulation and power calculations were used to determine error rates based on observed control coefficients of variation (CV) for 8 laboratories over a range of effect levels. Average C. dubia control reproduction among laboratories was 20 to 40 offspring per female, and the 75th percentile CV was 0.10 to 0.31, reflecting a range in laboratory performance. The 2 approaches behave similarly for CVs of 0.2 to 0.3. At effects <10%, as CV decreases, TST is less likely to declare toxicity and NOEC is more likely to do so. Laboratory performance affects whether a sample is declared toxic and influences the probability of false-positive (and -negative) error rates using either approach. At the 75th percentile control CV observed for each laboratory, 4 laboratories would achieve approximately a 5% false-positive rate using 13 or fewer replicates for this test method. For the remaining 4 laboratories, more replicates would be needed to achieve a 5% false-positive rate. The present analyses demonstrate how false-positive rates are influenced by laboratory performance and WET test design. Environ Toxicol Chem 2019;38:511-523. Published 2019 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.


Assuntos
Testes de Toxicidade/métodos , Animais , Cladóceros/efeitos dos fármacos , Cladóceros/fisiologia , Interpretação Estatística de Dados , Feminino , Reprodução/efeitos dos fármacos , Estados Unidos , United States Environmental Protection Agency , Poluentes Químicos da Água/toxicidade
10.
Ecotoxicol Environ Saf ; 162: 663-672, 2018 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-30056931

RESUMO

Antimicrobials are commonly used in aquaculture to treat infectious diseases in fish. The overuse of these chemicals, however, has made them a contamination source for the aquatic environments. In this study, single and combined effects of florfenicol (FLO) and oxytetracycline (OTC), two antimicrobials widely used in the fish farming, were evaluated in acute and chronic toxicity tests using the tropical cladoceran Ceriodaphnia silvestrii as a model species. Also, a preliminary risk characterization of FLO and OTC for zooplankton was carried out, taking into account different exposure scenarios. The results obtained revealed that FLO and OTC have adverse effects on the mobility, reproduction and population growth rate of C. silvestrii in single exposures. In addition, mixture effects on the C. silvestrii were more severe than predicted effects based on the Concentration Addition model, showing a synergistic deviation for the mobility and a dose-level dependent deviation for the reproduction (synergism at higher levels than EC60). In relation to the risk characterization, risk quotients (RQs) exceeded 1 for chronic toxicity data obtained in both OTC and mixture exposures, indicating that the concentrations of these chemicals in Brazilian freshwater bodies could potentially present risks for the reproduction of zooplankton species in tropical regions. The RQs obtained for the mixtures were higher than those obtained for each chemical separately. Therefore, it is highly recommended that RQs are derived from single and mixture exposure data in order to obtain a more accurate risk characterization.


Assuntos
Antibacterianos/toxicidade , Cladóceros/efeitos dos fármacos , Oxitetraciclina/toxicidade , Tianfenicol/análogos & derivados , Poluentes Químicos da Água/toxicidade , Zooplâncton/efeitos dos fármacos , Animais , Cladóceros/fisiologia , Feminino , Locomoção/efeitos dos fármacos , Masculino , Reprodução/efeitos dos fármacos , Tianfenicol/toxicidade , Testes de Toxicidade Aguda , Testes de Toxicidade Crônica , Zooplâncton/fisiologia
11.
Ecotoxicol Environ Saf ; 163: 238-244, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30056337

RESUMO

Neonicotinoid insecticides are a group of plant protectants frequently detected in surface waters at low concentrations. Aquatic invertebrates therefore have the potential to be exposed chronically to low concentrations of neonicotinoids. The cladocerans Daphnia magna and Ceriodaphnia dubia are among the most commonly used invertebrate test species in aquatic toxicology. Both species are known to be acutely insensitive to neonicotinoids, and while chronic toxicity has been characterized for D. magna, little research has been conducted with C. dubia. In the present study we conducted 7-d static-renewal life cycle tests for 6 neonicotinoids (acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, and thiamethoxam) with C. dubia, and a 21-d test with imidacloprid with D. magna. 7-d LC50s for C. dubia ranged from 8.42 mg L-1 for imidacloprid to > 100 mg L-1 for clothianidin; 7-d reproduction EC50s were 2.98 for thiacloprid, to > 67 mg L-1 for dinotefuran. D. magna were less sensitive than C. dubia to imidacloprid, by 4-fold for lethality and 1.5-fold for reproduction; however, acute-to-chronic ratios (ACRs) were similar. ACRs, based on 48-h acute LC50s and 7- or 21-d chronic reproduction EC10s, ranged from 5.4 for acetamiprid to 53.0 for imidacloprid (mean 36.6, CV = 51%). Chronic toxicity values for both species were orders of magnitude greater than concentrations reported in the environment, and thus hazard to these cladocerans is negligible.


Assuntos
Cladóceros/efeitos dos fármacos , Exposição Ambiental , Inseticidas/farmacologia , Neonicotinoides/farmacologia , Poluentes Químicos da Água/farmacologia , Animais , Cladóceros/fisiologia , Daphnia/efeitos dos fármacos , Daphnia/fisiologia , Guanidinas/farmacologia , Imidazóis/farmacologia , Invertebrados/efeitos dos fármacos , Estágios do Ciclo de Vida , Nitrocompostos/farmacologia , Oxazinas/farmacologia , Piridinas/farmacologia , Reprodução , Tiametoxam , Tiazinas/farmacologia , Tiazóis/farmacologia
12.
Artigo em Inglês | MEDLINE | ID: mdl-29120696

RESUMO

Standardized ecotoxicity bioassays show some limits to assess properly long-term residual toxicity of complex mixture of pollutants often present at low concentration, such as stormwaters. Among invertebrate organisms used for ecotoxicity testing, the microcrustacean Ceriodaphnia dubia (C. dubia) is considered as one of the most sensitive, especially regarding reproduction impairment as a toxicity endpoint. Consequently, this work explores the interest to perform a multigenerational assay based on the study of the reproduction of C. dubia to assess long-term ecotoxicity of complex mixture, using stormwater samples. With this in mind, a battery of standardized bioassays (Daphnia magna mobility, Pseudokirchneriella subcapitata population growth, Heterocypris incongruens growth and one generation C. dubia reproduction inhibition assays) was performed in parallel to a three generation C. dubia reproduction inhibition assay on 2 stormwater samples. Results highlighted that while all standardized bioassays failed to reveal residual toxicity in the stormwater samples, the C. dubia multigenerational assay exhibited an higher sensitivity than the previous ones. No adverse effect was observed for the first exposed generation, but an increase in mortality and a reproduction disturbance was obtained in the second and third exposed generation depending of the sample. Further experiments are now needed to optimize the exposure protocol of this multigenerational assay.


Assuntos
Bioensaio/métodos , Cladóceros/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Bioensaio/instrumentação , Cidades , Cladóceros/fisiologia , Reprodução/efeitos dos fármacos
13.
Environ Toxicol Chem ; 37(1): 49-60, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28833434

RESUMO

Although it is well known that increasing water hardness and dissolved organic carbon (DOC) concentrations mitigate the toxicity of aluminum (Al) to freshwater organisms in acidic water (i.e., pH < 6), these effects are less well characterized in natural waters at circumneutral pHs for which most aquatic life regulatory protection criteria apply (i.e., pH 6-8). The evaluation of Al toxicity under varying pH conditions may also be confounded by the presence of Al hydroxides and freshly precipitated Al in newly prepared test solutions. Aging and filtration of test solutions were found to greatly reduce toxicity, suggesting that toxicity from transient forms of Al could be minimized and that precipitated Al hydroxides contribute significantly to Al toxicity under circumneutral conditions, rather than dissolved or monomeric forms. Increasing pH, hardness, and DOC were found to have a protective effect against Al toxicity for fish (Pimephales promelas) and invertebrates (Ceriodaphnia dubia, Daphnia magna). For algae (Pseudokirchneriella subcapitata), the protective effects of increased hardness were only apparent at pH 6, less so at pH 7, and at pH 8, increased hardness appeared to increase the sensitivity of algae to Al. The results support the need for water quality-based aquatic life protection criteria for Al, rather than fixed value criteria, as being a more accurate predictor of Al toxicity in natural waters. Environ Toxicol Chem 2018;37:49-60. © 2017 SETAC.


Assuntos
Alumínio/toxicidade , Organismos Aquáticos/fisiologia , Carbono/análise , Água Doce , Compostos Orgânicos/análise , Animais , Organismos Aquáticos/efeitos dos fármacos , Clorófitas/efeitos dos fármacos , Cladóceros/efeitos dos fármacos , Cladóceros/fisiologia , Cyprinidae/fisiologia , Daphnia/efeitos dos fármacos , Daphnia/fisiologia , Dureza , Concentração de Íons de Hidrogênio , Invertebrados/efeitos dos fármacos , Invertebrados/fisiologia , Solubilidade , Testes de Toxicidade Aguda , Testes de Toxicidade Crônica , Poluentes Químicos da Água/toxicidade , Qualidade da Água
14.
Environ Toxicol Chem ; 37(1): 80-90, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28833517

RESUMO

The bioavailability of aluminum (Al) to freshwater aquatic organisms varies as a function of several water chemistry parameters, including pH, dissolved organic carbon (DOC), and water hardness. We evaluated the ability of multiple linear regression (MLR) models to predict chronic Al toxicity to a green alga (Pseudokirchneriella subcapitata), a cladoceran (Ceriodaphnia dubia), and a fish (Pimephales promelas) as a function of varying DOC, pH, and hardness conditions. The MLR models predicted toxicity values that were within a factor of 2 of observed values in 100% of the cases for P. subcapitata (10 and 20% effective concentrations [EC10s and EC20s]), 91% of the cases for C. dubia (EC10s and EC20s), and 95% (EC10s) and 91% (EC20s) of the cases for P. promelas. The MLR models were then applied to all species with Al toxicity data to derive species and genus sensitivity distributions that could be adjusted as a function of varying DOC, pH, and hardness conditions (the P. subcapitata model was applied to algae and macrophytes, the C. dubia model was applied to invertebrates, and the P. promelas model was applied to fish). Hazardous concentrations to 5% of the species or genera were then derived in 2 ways: 1) fitting a log-normal distribution to species-mean EC10s for all species (following the European Union methodology), and 2) fitting a triangular distribution to genus-mean EC20s for animals only (following the US Environmental Protection Agency methodology). Overall, MLR-based models provide a viable approach for deriving Al water quality guidelines that vary as a function of DOC, pH, and hardness conditions and are a significant improvement over bioavailability corrections based on single parameters. Environ Toxicol Chem 2018;37:80-90. © 2017 SETAC.


Assuntos
Alumínio/toxicidade , Organismos Aquáticos/fisiologia , Água Doce/química , Guias como Assunto , Testes de Toxicidade Crônica , Qualidade da Água , Animais , Organismos Aquáticos/efeitos dos fármacos , Clorófitas/efeitos dos fármacos , Clorófitas/fisiologia , Cladóceros/efeitos dos fármacos , Cladóceros/fisiologia , Cyprinidae/fisiologia , Modelos Lineares , Especificidade da Espécie , Água/química , Poluentes Químicos da Água/toxicidade
15.
Glob Chang Biol ; 24(1): e139-e158, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28833814

RESUMO

Recent anthropogenic climate change and the exponential increase over the past few decades of Saharan dust deposition, containing ecologically important inputs of phosphorus (P) and calcium (Ca), are potentially affecting remote aquatic ecosystems. In this study, we examine changes in cladoceran assemblage composition and chlorophyll-a concentrations over the past ~150 years from high-resolution, well-dated sediment cores retrieved from six remote high mountain lakes in the Sierra Nevada Mountains of Southern Spain, a region affected by Saharan dust deposition. In each lake, marked shifts in cladoceran assemblages and chlorophyll-a concentrations in recent decades indicate a regional-scale response to climate and Saharan dust deposition. Chlorophyll-a concentrations have increased since the 1970s, consistent with a response to rising air temperatures and the intensification of atmospheric deposition of Saharan P. Similar shifts in cladoceran taxa across lakes began over a century ago, but have intensified over the past ~50 years, concurrent with trends in regional air temperature, precipitation, and increased Saharan dust deposition. An abrupt increase in the relative abundance of the benthic cladoceran Alona quadrangularis at the expense of Chydorus sphaericus, and a significant increase in Daphnia pulex gr. was a common trend in these softwater lakes. Differences in the magnitude and timing of these changes are likely due to catchment and lake-specific differences. In contrast with other alpine lakes that are often affected by acid deposition, atmospheric Ca deposition appears to be a significant explanatory factor, among others, for the changes in the lake biota of Sierra Nevada that has not been previously considered. The effects observed in Sierra Nevada are likely occurring in other Mediterranean lake districts, especially in softwater, oligotrophic lakes. The predicted increases in global temperature and Saharan dust deposition in the future will further impact the ecological condition of these ecosystems.


Assuntos
Cladóceros/fisiologia , Mudança Climática , Poeira , Lagos/química , África do Norte , Animais , Biota , Ecossistema , Espanha , Temperatura Ambiente
16.
Sci Total Environ ; 610-611: 1222-1238, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-28851143

RESUMO

Information from effects of pesticides in sediments at an ecosystem level, to validate current and proposed risk assessment procedures, is scarce. A sediment-spiked outdoor freshwater microcosm experiment was conducted with fludioxonil (lipophilic, non-systemic fungicide) to study exposure dynamics and treatment-related responses of benthic and pelagic macroinvertebrates and zooplankton. Besides blank control and solvent control systems the experiment had six different treatment levels (1.7-614mga.s./kg dry sediment) based around the reported 28-d No Observed Effect Concentration (NOEC) for Chironomus riparius (40mga.s./kg dry sediment). Twelve systems were available per treatment of which four were sacrificed on each of days 28, 56 and 84 after microcosm construction. Fludioxonil persisted in the sediment and mean measured concentrations were 53-82% of the initial concentration after 84days. The dissipation rate increased with the treatment level. Also exposure concentrations in overlying water were long-term, with highest concentrations 28days after initiation of the experiment. Sediment-dwelling Oligochaeta and pelagic Rotifera and Cladocera showed the most pronounced treatment-related declines. The most sensitive sediment-dwelling oligochaete was Dero digitata (population NOEC 14.2mga.s./kg dry sediment). The same NOEC was calculated for the sediment-dwelling macroinvertebrate community. The most sensitive zooplankton species was the cladoceran Diaphanosoma brachyurum (NOEC of 1.6µga.s./L in overlying water corresponding to 5.0mga.s./kg dry sediment). At the two highest treatments several rotifer taxa showed a pronounced decrease, while the zooplankton community-level NOEC was 5.6µga.s./L (corresponding to 14.2mga.s./kg dry sediment). Zooplankton taxa calanoid Copepoda and Daphnia gr. longispina showed a pronounced treatment-related increase (indirect effects). Consequently, an assessment factor of 10 to the chronic laboratory NOECs of Chironomus riparius (sediment) and Daphnia magna (water) results in a regulatory acceptable concentration that is sufficiently protective for both the sediment-dwelling and pelagic organisms in the microcosms.


Assuntos
Organismos Aquáticos/fisiologia , Dioxóis/toxicidade , Ecossistema , Fungicidas Industriais/toxicidade , Pirróis/toxicidade , Poluentes Químicos da Água/toxicidade , Zooplâncton/fisiologia , Animais , Chironomidae/fisiologia , Cladóceros/fisiologia , Copépodes/fisiologia , Daphnia/fisiologia , Dioxóis/análise , Água Doce , Fungicidas Industriais/análise , Sedimentos Geológicos/química , Oligoquetos/fisiologia , Fitoplâncton , Pirróis/análise , Rotíferos/fisiologia , Poluentes Químicos da Água/análise
17.
Bull Environ Contam Toxicol ; 100(1): 69-75, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29279993

RESUMO

The acute toxicity of silver to Ceriodaphnia dubia was investigated in laboratory reconstituted waters as well as in natural waters and reconstituted waters with natural organic matter. The water quality characteristics of the laboratory reconstituted waters were systematically varied. The parameters that demonstrated an ability to mitigate the acute toxic effects of silver were chloride, sodium, organic carbon, and chromium reducible sulfide. Factors that did not have a consistent effect on the acute toxicity of silver to C. dubia, at least over the range of conditions tested, included hardness, alkalinity, and pH. The biotic ligand model was calibrated to the observed test results and found to be of use in quantifying the effect of changing water quality characteristics on silver bioavailability and toxicity. The model generally predicted silver toxicity within a factor of two and should be useful in modifying water quality criteria.


Assuntos
Cladóceros/fisiologia , Água Doce/química , Prata/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Cloretos , Cladóceros/efeitos dos fármacos , Sódio , Testes de Toxicidade Aguda , Qualidade da Água/normas
18.
Environ Pollut ; 227: 451-459, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28486188

RESUMO

Elevated temperatures and nutrients can favor phytoplankton dominance by cyanobacteria, which can be toxic to zooplankton. There is growing awareness that maternal effects not only are common but can also significantly impact ecological interactions. Although climate change is broadly studied, relatively little is known regarding its influence on maternal effects in zooplankton. Given that lakes are sentinels for climate change and that elevated temperatures and nutrient pollution can favor phytoplankton dominance by toxic cyanobacteria, this study focused on elucidating the effects of maternal exposure to elevated temperatures on the tolerance of zooplankton offspring to toxic cyanobacteria in the diet. Three different maternal thermal environments were used to examine population fitness in the offspring of two cladoceran species that vary in size, including the larger Daphnia similoides and the smaller Moina macrocopa, directly challenged by toxic Microcystis. Daphnia and Moina mothers exposed to elevated temperatures produced offspring that were more resistant to Microcystis. Such findings may result from life-history optimization of mothers in different temperature environments. Interestingly, offspring from Moina fed with toxic Microcystis performed better than Daphnia offspring, which could partially explain the dominance of small cladocerans typically observed during cyanobacterial blooms. The present study emphasizes the importance of maternal effects on zooplankton resistance to cyanobacteria mediated through environmental warming and further highlights the complexities associated with the abiotic factors that influence zooplankton-cyanobacteria interactions.


Assuntos
Cladóceros/efeitos dos fármacos , Daphnia/efeitos dos fármacos , Microcistinas/toxicidade , Microcystis , Animais , Cladóceros/fisiologia , Mudança Climática , Cianobactérias , Daphnia/fisiologia , Dieta , Tolerância a Medicamentos , Comportamento Alimentar , Lagos , Fitoplâncton , Zooplâncton
19.
Bull Environ Contam Toxicol ; 99(1): 23-26, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28526924

RESUMO

The effects of water pH on life history parameters of Bosmina tripurae have been studied to determine the most suitable water pH desired for the maximum growth and development of this newly discovered cladoceran species. The study was carried out under the laboratory condition at 20 ± 2°C. Five pH ranges 5.0 ± 0.2, 6.0 ± 0.2, 7.0 ± 0.2, 8.0 ± 0.2 and 9.0 ± 0.2 with six replicates for each pH consisting of one animal in each Petri dish (80 × 15 mm) were used for the study. 20 mL of respective test medium was maintained with Chlorella sp. (2 × 104 ± 0.03 cells mL-1) in each Petri dish throughout the experiment. Thirty (30) animals were observed daily to investigate different life history parameters like total life span, age at maturity, number of eggs, neonates and egg batches etc. at different condition. From the study it was found that acidic water (pH 5 ± 0.2) is more suitable for the culture of Bosmina tripurae in laboratory condition.


Assuntos
Cladóceros/fisiologia , Água Doce/química , Concentração de Íons de Hidrogênio , Animais , Chlorella , Cladóceros/efeitos dos fármacos , Ácidos Hidroxâmicos , Estágios do Ciclo de Vida , Vorinostat , Água
20.
Environ Toxicol Chem ; 36(10): 2698-2714, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28558138

RESUMO

A lotic mesocosm study was carried out in 20-m-long channels, under continuous, environmentally realistic concentrations of copper (Cu) in low, medium, and high exposures (nominally 0, 5, 25, and 75 µg L-1 ; average effective concentrations <0.5, 4, 20, and 57 µg L-1 respectively) for 18 mo. Total abundance, taxa richness, and community structure of zooplankton, macroinvertebrates, and emerging insects were severely affected at Cu treatment levels of 25 and 75 µg L-1 . Some taxa were sensitive to Cu, including gastropods such as Lymnaea spp. and Physa sp., crustaceans such as Chydorus sphaericus, Gammarus pulex, and Asellus aquaticus, rotifers such as Mytilina sp. and Trichocerca sp., leeches such as Erpobdella sp., and the emergence of dipteran insects such as Chironomini. Other taxa appeared to be tolerant or favored by indirect effects, as in Chironimidae larvae, the emergence of Orthocladiinae, and the zooplankter Vorticella sp., which increased in the 25 and 75 µg L-1 treatments. After approximately 8 mo of Cu exposure, the macroinvertebrate community in the high treatment was decimated to the point that few organisms could be detected, with moderate effects in the medium treatment, and very slight effects in the low-Cu treatment. Subsequently, most taxa in the high-Cu exposure began a gradual and partial recovery. By the end of the study at 18 mo, macroinvertebrate taxa richness was similar to control richness, although overall abundances remained lower than controls. After 18 mo of copper exposure, a no-observed-effect concentration at the community level for consumers was set at 5 µg L-1 (4 µg L-1 as average effective concentration), and a lowest-observed-effect concentration at 25 µg L-1 (20 µg L-1 as average effective concentration). Environ Toxicol Chem 2017;36:2698-2714. © 2017 SETAC.


Assuntos
Cobre/toxicidade , Invertebrados/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Cladóceros/efeitos dos fármacos , Cladóceros/fisiologia , Ecossistema , Água Doce , Invertebrados/fisiologia , Rotíferos/efeitos dos fármacos , Rotíferos/fisiologia , Estações do Ano , Zooplâncton/efeitos dos fármacos , Zooplâncton/fisiologia
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